Harry Bloomfield wrote:
Dan S. MacAbre presented the following explanation :
In case no-one else has any suggestions, I find that those Benzyl
Alcohol paint strippers soften up things like that - even when you
might not want them to :-) I've used them on acrylic sealers when
nothing else seems to work, but it also seems to soften up some of
those ready-mixed plaster repair fillers, which can be annoying; but
at least I know to be careful with it now. TBH, it's the only sort of
stripper I'll buy from now on, since it's the only thing I ever found
that works on emulsion, too. Takes hours to work, though. And it's
supposed to be non-toxic (at least it is ATM) and it is low-vapour.
Costs about £30 for a big plastic bottle, so might not be economic for
a small job, but if you will be stripping paint in the future...

I don't want the underlying paint surface to be damaged..

Ah. That would definitely be a problet :-)